Coherent light sources, such as lasers, are attractive light sources for projection displays; however coherent light produces image defects in projected images, including speckle and non-uniformities. Optical fibers can be used to convey light from the coherent light sources to a light modulator. While vibration of the optical fibers can be used to reduce the image defects, previously used mechanical shakers, such as shakers, motors, offset shafts, piezo-electrics, are complicated and can lead to damage of the optical fibers. Similar effects can be produced by vibrating optical components interacting with coherent light, with damage again possibly occurring when mechanical shakers are used.